Note: Descriptions are shown in the official language in which they were submitted.
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SELF-ALIGNING, DOUBLE WIRE CORNER BEAD FOR FIREPROOFING
STRUCTURAL STEEL MEMBER AND METHOD OF USING SAME
TECHNICAL FIELD
[0001] The present invention relates generally to a corner bead for
cementitious
fireproofing of structural steel members and, more particularly, to a device
that is self-aligning in
installation and allows the accurate gauging of the thickness of the
fireproofing material along
three surfaces.
BACKGROUND OF THE INVENTION
[0002] In the art of a corner bead for fireproofing structural steel,
prior approaches
conventionally include a v-bend corner bead having adjustable legs (flanges).
This type of corner
bead is mostly used in the plastering and stucco trades. The previously
utilized corner bead is
constructed of wires welded into a lattice that is v-shaped in section as
shown in Figure 1.
[0003] In installation, the longitudinal base wires of the v-shaped
corner bead are
attached with a tie wire either onto a metal lath or onto a wire mesh, and
further attached to the
steel member to be fireproofed as shown in Figure 2. At best, this allows for
distribution of the
fireproofing material along two surfaces after a complex negotiation of the
correct height of the
two flanges; to wit, to establish the correct fireproofing thickness, one must
establish the correct
height of the vertex by shrinking or expanding the distance between the legs
(flanges) of the
corner bead defined by the vertex. Using this technique, the alignment of the
corner bead with
the adjacent surface is difficult and great skill is required to install the
corner bead for
fireproofing structural steel.
[0004] The prior art includes many problems, including the difficulty
of properly
adjusting the traditional corner bead to the adjacent surface, the uneven
application of
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fireproofing material, and the lack of a dam for the wet cement material.
Despite these well-
known and long-existing problems, and a readily apparent market for a
solution, the prior art
does not disclose or suggest a viable, cost-effective solution to the
aforementioned problems of
the prior art.
[0005] Accordingly, a need exists for an improved corner bead to avoid
inaccuracy in
gauging the thickness of the fireproofing material and to allow easy
installation along three
surfaces. An improved self-aligning double wire corner bead is inexpensive to
manufacture and
easy to install.
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SUMMARY
[0006] The present invention provides a self-aligning, double wire
corner bead that
allows to make, in an accurate and quick manner, corners of a fireproofing
material around
structural steel members, said fireproofing material having uniform thickness
around the
structural steel member. This is accomplished by bending a single strip of
welded wire fabric of
pre-determined width along a plurality of longitudinally extending lines
(axes) to provide a
profile of a metal sheet having a plurality of dihedral angles, two wings of
the desired width, a
single wire membrane and a double wire membrane, said double wire membrane
comprising a
first leg and a second leg as substantially shown in Figures 4 and 5.
[0007] The angle at which each wing meets the single wire membrane and
a second
leg of the double wire membrane of the device, respectively, determines the
thickness of the
fireproofing material distributed around the structural steel member along
three surfaces. Further,
said thickness may be modified by changing the width of each respective wing.
The uniformity
in thickness of the fireproofing material distributed around three surfaces of
the structural steel
member is achieved by bending the first wing and the second wing at
approximately the same
angle in relation to the single wire membrane and the second leg of the double
wire membrane,
respectively. The uniformity in thickness of the fireproofing material
distributed around all
surfaces of the structural steel member in a contour type application is
achieved by using the
same width of the single metal strip bent to create an identical single metal
sheet profile for all
corners of the structural steel member.
[0008] It is further an object of the present invention to provide an
improved corner
bead for fireproofing structural steel without the need of adjusting the legs.
[0009] Another object of the present invention is to provide novel
means of installing
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the corner bead by easier attachment to the structural steel.
[0010] Another object of the present invention is to provide an
improved technique
for application of accurate thickness of fireproofing material along three
surfaces under any
construction condition for making said fireproofing of structural steel
members.
[0011] A further object of the present invention is to provide a dam
to form a
roughened surface on the first application of fireproofing material until it
hardens along three
surfaces.
[0012] While satisfying these and other related objectives, the
present invention
provides an improved, self-aligning, double wire corner bead for fireproofing
structural steel
which is very competitive from a mere economic standpoint. The corner bead of
the present
invention consists of a single strip of welded wire fabric cut to a desired
width for the
fireproofing thickness and bent along a plurality of longitudinal axes to form
a set of wings, a
single wire membrane, and a double wire membrane, said double wire membrane
having a first
leg and a second leg, said first leg seamlessly becoming said second leg
through a process of
bending of said double wire membrane such that said first leg is substantially
parallel to said
second leg, and wherein said single wire membrane and said double wire
membrane are attached
by the attachment means to the lath distributed around the structural steel
member.
[0013] In accordance with the present invention, the corner bead
includes a single
elongated strip of welded wire fabric of pre-determined width, said single
strip of welded wire
fabric comprising a set of flexible mesh strips as shown in Figure 3.
[0014] According to one embodiment of the present invention, the
improved double
wire corner bead allows each element of the bent wire mesh of the corner bead
to perform
different functions that are essential for the successful completion of the
fireproofing process
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along three surfaces.
[0015] The single wire membrane and the double wire membrane provide a
flat
portion of a grid (mesh) through which pneumatic or screw type fasteners
attach the mesh to the
structural steel at the appropriate location. In addition, the double-wire
membrane provides
additional support for two wings positioned at the opposite corners of the
steel structure member,
hence facilitating one piece of wire mesh to cover two corners and three
surfaces of the structure.
This easy application establishes automatic alignment of the corner bead along
three surfaces,
eliminates the cumbersome process of shrinking or expanding the distance
between the legs of
the traditional bead, as well as provides only one strip of metal of the
desired width to allow
fireproofing of two corners of the steel structure member along three surfaces
at the same time in
a contour-method application of the fireproofing material.
[0016] The width of the set of wings and/or the angle at which the
first and the
second wing meet the single wire membrane and the second leg of the double
wire membrane,
respectively, determines the thickness of the fireproofing material
distributed along three
surfaces by providing a rigid screed edge along a nose. Therefore, the correct
amount of
fireproofing material is distributed adjacent to the corner bead creating a
leveled application
throughout the surface.
[0017] The width of the set of wings also provides a dam to form a
roughened surface
on the first application of the fireproofing material until the fireproofing
material hardens. This
forming action allows successive application of the cement material to the
adjacent surface.
[0018] In another aspect, the present invention includes a method of
manufacturing
an improved self-aligning, double wire corner bead for fireproofing structural
steel comprising a
single strip of welded wire fabric cut to the desired width for the
fireproofing thickness and bent
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along a plurality of longitudinally extending lines (axes) to form a profile
of a metal sheet, a first
longitudinal line to define a first wing and a single wire membrane extending
laterally therefrom
at a first angle of approximately greater than 90 degrees but less than
approximately 180 degrees
relative to each other and wherein said single wire membrane is secured to a
structural steel
member and said first wing is configured to establish a desired thickness of
the fireproofing
material along two surfaces by providing a rigid screed edge along the nose, a
second
longitudinal line to define said single wire membrane and a first leg of a
double wire membrane
extending from said single wire membrane in a continuous manner and at a
second angle of
approximately 90 degrees relative to each other, a third longitudinal line to
define said first leg of
said double wire membrane and a second leg of said double wire membrane such
that said first
leg is positioned substantially parallel to said second leg (the second leg
substantially overlaps
the first leg), and wherein said double wire membrane is secured to said
structural steel member,
and a fourth longitudinal line to define a second wing and said second leg of
said double wire
membrane, said second leg extending downwardly from said second wing at a
third angle of
approximately greater than 90 degrees but less than approximately 180 degrees
relative to each
other, and wherein said third angle is substantially equal to said first
angle.
[0019] In a further aspect, the present invention includes a method of
finishing a set
of corners for cementitious fireproofing in a contour application of a set of
structural steel
members, the method comprising the steps of: selecting a corner bead
comprising a single strip
of welded wire fabric cut to the appropriate width for the fireproofing
thickness and bent along a
plurality of longitudinally extending lines, to provide a profile having a
plurality of dihedral
angles, wherein a first longitudinal line to define a first wing and a single
wire membrane
extending laterally therefrom at a first angle of approximately greater than
90 degrees but less
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than approximately 180 degrees relative to each other and wherein, said single
wire membrane is
secured to a structural steel member and a first wing is configured to
establish a desired thickness
of the fireproofing material along two surfaces by providing a rigid screed
edge along the nose, a
second longitudinal line to define said single wire membrane and a first leg
of a double wire
membrane extending from said single wire membrane in a continuous manner and
at a second
angle of approximately 90 degrees relative to each other, a third longitudinal
line to define said
first leg of said double wire membrane and a second leg of said double wire
membrane such that
said second leg is extending from said first leg of said double wire membrane
in a continuous
manner in such a way that said first leg is positioned substantially parallel
to the second leg (the
second leg substantially overlaps the first leg), and wherein said double wire
membrane is
secured to said structural steel member, and a fourth longitudinal line to
define a second wing
and said second leg of said double wire membrane, said second leg extending
downwardly from
said second wing at a third angle of approximately greater than 90 degrees but
less than
approximately 180 degrees relative to each other, and wherein said third angle
is substantially
equal to said first angle.
[0020] A dihedral angle (also called a face angle) is the internal
angle at which two
adjacent faces of each section member of the double wire corner bead is
delimited by the two
inner faces, e.g., angle al formed between adjacent faces of the first wing
and the single wire
membrane, angle a2 formed between adjacent faces of the second wing and the
second leg of the
double wire membrane and angle 13 formed between adjacent faces of the single
wire membrane
and the first leg of the double wire membrane. The fourth angle created along
the third
longitudinal line between the first and the second leg of the double wire
membrane is
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substantially zero (0) degrees so that the first leg and the second leg
substantially overlap each
other, and are approximately parallel, with respect to each other.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 is a perspective view of a small section of a corner
bead according to
the prior art.
[0022] Figure 2 is a cross-sectional schematic view of a fireproofing
structure
utilizing a prior art corner bead installed according to a contour method.
[0023] Figure 3 is a perspective view of an exemplary small section of
the corner
bead of the present invention bent along a longitudinal axis and manufactured
according to an
embodiment of the present invention.
[0024] Figure 4 is an enlarged cross-sectional schematic view of the
self-aligning,
double wire corner bead of the present invention.
[0025] Figure 5 is a cross-sectional schematic view of a fireproofing
structure
utilizing a self-aligning, double wire corner bead of the present invention
according to the
contour method.
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DETAILED DESCRIPTION
[0026] Referring to Figure 3, corner bead 10 includes a plurality of
longitudinal ribs
16 arranged substantially parallel with respect to a plurality of longitudinal
axes, including
longitudinal axis A and to each other, and a plurality of transverse ribs 18
distributed between
and extending substantially perpendicular to the plurality of longitudinal
axes and the plurality of
longitudinal ribs 16. A set of void areas 20 is defined by the plurality of
longitudinal ribs 16 and
the plurality of transverse ribs 18, such that each void area 20 is bounded by
at least two
longitudinal ribs 16 and at least two transverse ribs 18. A section of corner
bead 10 includes a
single strip of welded wire fabric cut to a predetermined length L and a
predetermined width W.
The predetermined length L and the predetermined width W correspond to a
predetermined
fireproofing thickness.
[0027] In a preferred embodiment, corner bead 10 is made of a suitable
metal, such as
16 gauge wire. Other suitable materials known in the art may be employed,
including suitable
plastics. In a preferred embodiment, corner bead 10 is a double welded wire
fabric.
[0028] In a preferred embodiment, corner bead 10 has a set of bends
integrally
formed in corner bead 10 along the plurality of longitudinal axes. Any number
of bends may be
employed. Longitudinal axis A defines first wing 12 and single wire membrane
11. First wing 12
and single wire membrane 11 form angle al of approximately greater than 90
degrees, but less
than approximately 180 degrees as further illustrated in Figures 4 and 5. A
set of edges of first
wing 12 defines a substrate to which nose 14 is attached. Nose 14, first wing
12, and second
wing 12' (shown in Figure 5) provide a rigid edge having a dam-like function,
as will be further
described below.
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[0029] In a preferred embodiment, nose 14 is made of a suitable
plastic, such as
polyvinyl chloride. Other suitable materials known in the art may be employed.
[0030] Referring to Figure 4, corner bead 10 is bent along a plurality
of longitudinal
lines 41, 42, 43, and 44, to provide a substantially continuous profile having
a plurality of
dihedral angles. Longitudinal line 44 defines first wing 12 and single wire
membrane 11
extending laterally therefrom at angle al Angle al is approximately greater
than 90 degrees, but
less than approximately 180 degrees. Each of noses 14 is attached to first
wing 12 and second
wing 12'. Longitudinal line 42 defines single wire membrane 11 and leg 31 of
double wire
membrane 30 extending from single wire membrane 11 in a continuous manner.
Single wire
membrane 11 and leg 31 are separated by angle 13. Angle 13 is approximately 90
degrees.
Longitudinal line 43 defines leg 31 of double wire membrane 30 and leg 31' of
double wire
membrane 30. Leg 31' is positioned substantially parallel to leg 31. Leg 31'
substantially
overlaps leg 31. Longitudinal line 41 defines second wing 12' and leg 31' of
double wire
membrane 30. Leg 31' extends away from second wing 12' at angle a2. Angle a2is
approximately greater than 90 degrees, but less than approximately 180
degrees.
[0031] In use, the improved, self-aligning, double wire corner bead 10
of the present
disclosure is utilized in a contour-like manner, surrounding a structural
steel member with
fireproofing material. Referring to Figure 5, single wire membrane 11 is
secured to structural
steel member 24. First wing 12 is configured to establish a desired thickness
of fireproofing
material 22 along two surfaces of the structural steel member by providing a
rigid screed edge to
which nose 14 is attached. Double wire membrane 30 is secured to structural
steel member 24, as
will be further described below. Fireproofing material 22 surrounds the
dimensions of the
structural steel member 24 in a contour-like manner, tracing structural steel
member 24 in all
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dimensions. The single strip of corner bead 10 allows uniform distribution of
fireproofing
material 22 along three surfaces, surfaces Si, S2, and S3.
[0032] Referring to Figures 4 and 5, the width of the wings 12 and 12'
determines
distances Di, D2, and D3, and defines generally planar surfaces Si, S2, and S3
forming a set of
corners of fireproofing material 22 distributed around structural steel member
24. Similarly, any
of distances Di, D2, and D3 are optionally altered by changing angles al and
a2. Angles al and
a2 are substantially equal and measure approximately greater than 90 degrees,
but less than 180
degrees. Angle 13 measures approximately 90 degrees. For example, the smaller
(less obtuse)
angle al is between first wing 12 and the single wire membrane 11 the longer
distance Di is
between lath 26 and surface Si, and the shorter distance D3 is between lath 26
and surface S2.
Similarly, the less obtuse angle a2 is between second wing 12' and leg 31' of
double wire
membrane 30, the longer distance D2 is and the shorter distance Di is making
distributed
fireproofing material 22 thicker along surface S3 in relation to a thinner
strip of fireproofing
material 22 along surface Si.
[0033] In a preferred embodiment, the determination of angles al and
a2 should be
such that a uniform thickness of fireproofing material 22 along surface Si is
achieved.
[0034] In one embodiment, lath 26 is distributed around structural
steel member 24.
Single wire membrane 11 is attached through lath 26 into structural steel
member 24 by
pneumatic fastener 28 at a single fastening position on single wire membrane
11. Other joining
or attaching means known in the art, such as welded pins or screws, may be
employed.
[0035] In another embodiment, each of single wire membrane 11 and
double wire
membrane 30 is attached to structural steel member 24 by pneumatic fastener 28
at a single
fastening position on double wire membrane 30.
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[0036] In another embodiment, leg 31 and leg 31' of double wire
membrane 30 are
attached through lath 26 into structural steel member 24 by pneumatic fastener
28 at a single
fastening position on double wire membrane 30. Other joining or attaching
means known in the
art, such as welded pins or screws, may be employed. According to one
embodiment of the
present invention, lath 26 is optionally distributed along the entire
perimeter of structural steel
member 24 to be fireproofed (not shown). In another embodiment, lath 26 is
distributed along a
portion of the perimeter of structural steel member 24.
[0037] In other embodiments, any number of fastening positions and
locations may
be employed.
[0038] The width of first wing 12 and second wing 12' along with nose
14 attached
to the outer edges of both wings serves as a dam during the process of
fireproofing. Fireproofing
material 22 is then sprayed onto lath 26 and screened off using the location
of nose 14 to
determine the finished thickness of fireproofing material 22.
[0039] Referring to Figure 5, in a shop application, i.e.,
fireproofing material 22 is
applied to structural steel member 24 in a pre-fabrication facility, the
cementitious composition
is sprayed or poured one layer at a time on a surface of lath 26 positioned
horizontally. Structural
steel member 24 is then rotated 90 degrees and the adjacent surfaces are
positioned horizontally
to allow easy application of fireproofing material 22. With this process in
place, each successive
spraying is performed which allows hardening of fireproofing material 22
before the next
rotation of structural steel member 24. As can be seen, the dam-like
functionality of corner bead
according to one embodiment of the present invention is critical as it
provides an appropriate
keying surface to bond the subsequent layers of fireproofing material 22. Each
structural steel
member 24 is turned to uniformly apply the cementitious material to all
surfaces.
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[0040] It will be appreciated by those skilled in the art that any
type of member may
be employed.
[0041] In a field application on a job site, structural steel members
24 are erected into
a structure prior to fireproofing, and all surfaces of structural steel member
24 may be sprayed or
troweled onto the surface of lath 26 at the same time (not shown).
[0042] It will be appreciated that the invention is not restricted to
the particular
embodiment that has been described, and that variations may be made therein
without departing
from the scope of the invention as defined in the appended claims, as
interpreted in accordance
with principles of prevailing law, including the doctrine of equivalents or
any other principle that
enlarges the enforceable scope of a claim beyond its literal scope. Unless the
context indicates
otherwise, a reference in a claim to the number of instances of an element, be
it a reference to
one instance or greater than one instance, requires at least the stated number
of instances of the
element, but is not intended to exclude from the scope of the claim a
structure or method having
more instances of that element than stated. The word "comprise" or a
derivative thereof, when
used in a claim, is used in a nonexclusive sense that is not intended to
exclude the presence of
other elements or steps in acclaimed structure or method.
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